@Lucuis , when creating a new season, you need to add at least one class to it to before clicking the Create button will work. There is a known issue that the Create season screen does not warn you when this happens.
If you created a new season with the same year that already exists, it will overwrite the existing season with the new one.
In google chrome, do the following.
Go to your season that you can't click the save button.
OSX - Shift + Command + i
Windows - Shift + Ctrl + i
Then click the Console label on the top of the new panel that is displayed.
Now, reload/refresh the page (Ctrl + R or Command + R)
After reloading the page, do you see any red text?